Lesson 20 Vertebrates II Marine Biology Vertebrates Animals

Lesson 20: Vertebrates II Marine Biology

Vertebrates: Animals with a backbone l l l 2 We’ve been learning about marine life in the sub-phylum vertebrata What are some common features of this sub-phylum? Today we’ll conclude our survey of life in the sea by taking a look at the class mammalia Classification Overview Common Vertebrates Phlyum Chordata Classes Chondrichthyes Actinopterygii Reptilia Mammalia Subphylum Vertebrata

Warm-blooded animals l l Marine mammals are warm-blooded: they keep a constant internal temperature They also share other characteristics: – – – 3 Give birth to live offspring Hair on some part of the body Mammary glands to provide milk to young Classification Overview Common Mammalian Orders Sub-Phlyum Vertebrata Class Mammalia Orders Pinnipedia – Seals, Sea Lions, Walrus Cetacea – Dolphins, Whales Sirenia – Mantees

Heat loss is high in the ocean l l Heat loss in the water is faster than in the air, even at the same temperature So how do marine mammals maintain their body temperatures? – 4 Countercurrent heat exchange - Insulation (blubber, fur) - Behavioral strategies (coming to the surface to get warm) - High metabolism Heat from blood traveling through the arteries is transferred to blood traveling back to the body core from the extremities, so that heat isn’t lost to the environment

Pinnipeds: Animals with “fin feet” 5 l Order Pinnipedia refers to mammals with large finlike flippers including sea lions, seals and walruses l Pinnipeds come onto the shore to breed and, like other mammals, give birth to live young l Do you know the difference between a seal and a sea lion?

Seals and sea lions ear flap Steller Sea Lion Photo: NOAA Spotted l Seals lack ear flaps and Seal have rear flippers that point backward 6 Photo: NOAA National Marine Mammal Laboratory l Because they can’t rotate their flippers, they don’t move very well out of water l Sea lions have ear flaps l Sea lions can rotate their flippers forward and thus are mobile out of water

Order Cetacea: Whales, dolphins, and porpoises l l Cetaceans are highly adapted to life underwater They share several characteristics – – – 7 No hind limbs Muscular tail Fish-like body form Blowhole at the top of the head for breathing Blubber (fat layers) to insulate the body

Baleen whales: Suborder Mysticeti l Did you know that some whales don’t have teeth? l Baleen whales trap food in their mouths using a broom-like filter that catches krill and small fish l Many of the largest whales belong to this sub-order Photo: NOAA 8

Let’s meet some baleen whales Photos: NOAA Blue whales, shown above, can be up to 90 ft long l They are identified by their characteristic skin pigmentation l 9 l l Humpback whales are known for their complex songs Males use these songs to communicate and to court females

Toothed whales: Suborder Odontoceti 10 l Unlike the baleen whales, marine mammals in the suborder Odontoceti have teeth l This suborder includes dolphins, orcas (killer whales) and the sperm whale l These mammals use sound waves (echolocation) to help find their way underwater, to communicate and in some cases to hunt prey

Let’s meet some toothed whales 11 The sperm whale primarily hunts deep ocean squid, including the giant squid, which can grow over 50 feet long Photo: NOAA Pacific white-sided dolphins (below) are very social mammals, usually traveling in groups of 10100 dolphins

Dolphins and porpoises 12 Photos: NOAA Dolphins and porpoises are both toothed whales, but they are in separate families Dolphins (Delphinidae) Porpoises (Phocoenidae) Teeth are cone-shaped Teeth are flattened Beak-shaped snout Blunt snout Hooked or curved dorsal fin Small, triangular dorsal fin Often seen at surface Seen only briefly at surface

Student activity In today’s activity, you will practice identifying marine mammals 13